a. Field of the Invention
The instant invention relates generally to detection methods for use in medical systems. In particular, the instant invention relates to prolapse and tool/device dislodgement detection systems and methods.
b. Background Art
It is known to park a medical tool/device within the body of a patient, for example, during a medical procedure. The tool/device is usually considered parked when the tool is inserted into a structure like an artery or a vein and has reached a desired location. For example, a cannulation catheter used for left-heart lead implantation may be parked inside the coronary sinus. Alternatively, the tool/device may be deemed parked when the tool is affixed to the tissue at a desired location. There are other examples where a medical tool or device is parked inside the body of a patient, for example, where a reference electrode is parked at a desired location to provide a stable reference point or origin for a navigation and localization system (e.g., parking a navigational reference catheter so that by moving a mapping catheter within a heart chamber coordinates may be acquired). Unfortunately, it is also known that a parked or stationary medical tool/device may become dislodged during the procedure, for example, by an external force being applied against the parked medical tool. U.S. Patent Publication 2008/0161681 entitled NAVIGATIONAL REFERENCE DISLODGEMENT DETECTION METHOD & SYSTEM to Hauck, assigned to the common assignee of the present invention and hereby incorporated by reference in its entirety, disclose a system for monitoring for dislodgement of a navigational reference electrode away from an initial (desired) reference location.
It is also well known to advance a guidewire through a patient's vasculature to a destination site and then to insert and advance a catheter or other tool to the site with the aid of the guidewire. During this process, however, the guidewire tip may prolapse, or in other words, the guidewire distal tip may bend or fold on itself (i.e., back along its route). Guidewire tip prolapse may occur when the guidewire is accidentally inserted into a branch in the blood vessel (i.e., the guide tip being caught in a bifurcation) or when the guidewire tip encounters a blockage in the blood vessel turning the tip back against itself (i.e., back along its route) inside the blood vessel. Traditionally, the process of advancing the guidewire is performed under constant fluoroscopy, which allows a physician to immediately identify any prolapse of the guidewire tip. It is therefore known to detect guidewire prolapse through visual recognition by the physician using live fluoroscopy. While detection using this approach is accurate, it would nonetheless be desirable to reduce or eliminate the need for (or amount of) live fluoroscopy so as to reduce patient exposure while at the same time retaining the capability of recognizing guidewire prolapse.
There is therefore a need to minimize or eliminate one or more of the problems set forth above.